1. Technical Field
This disclosure is generally related to the systems and methods of regulating an output of a device, and more particularly, related to systems and methods of regulating an output of a device using a transition rate of a quantized signal, where the transition rate is proportional to an output of the device, for example an LED backlight.
2. Description of the Related Art
Control systems for regulating a device are well known. Typically, control systems regulate devices by employing a feedback loop. However, when the device has a wide dynamic response range, it may become difficult to rapidly and accurately regulate the device over the response range, especially at the extrema of the response range.
As a non-limiting example, the output of a multi-color LED (light emitting diode) backlight is regulated to provide color and luminance control. Currently, one type of control system for a multi-color LED backlight may include photo sensors with color filters, linear or log amplifiers, and analog to digital converters. This sort of control system has several disadvantages. One disadvantage, among others, is that multi-color LED backlights are frequently intended to be used in relatively small spaces, and such a control system takes up too much of the available space. Another disadvantage is cost and the number of components in such a control system. The more components in a control system, the higher the chance that at least one of the components will malfunction.
Some control systems for a multi-color LED backlight may include a single unfiltered photo sensor for luminance measurement and a “color correction mode” where each color of LED source is cycled through and measured individually. However, this type of control system may require periodic maintenance activity for color correction and does not provide feedback to correct for dynamic amplitude, temperature and supply variations.
Thus, there exists a need for a control system for regulating devices such as backlights and other devices such as rotary motors that have a wide range of dynamic response. It is desired that such a control system provide fast measurement of an output from the regulated device and transient control of the regulated device. It is further desired that such a control system can be made to dynamically track with the sample speed of data related to the output of the regulated device. In addition, it is desired that such a control system be economical and be fault tolerant to timing errors.